This Core will serve as a clinical specimen repository, a source for purified proteins, a protein reference center and a tissue analysis facility for the individual Projects 1-4. Serum, urine, plasma cells (blood and/or bone marrow) and tissue samples on more than 900 patients with AL amyloidosis have been collected, stored and cataloged. In addition, recombinant clones of several light chain (LC) proteins/subdomains are available. LC proteins are purified from clinical or recombinant sources using preparative separation techniques that include conventional column chromatography, HPLC and polyacrylamide gel electrophoresis (PAGE). Purified LC proteins are provided to all projects on request. Core A will assess in vitro and transgenic expression of LC proteins for Project 1 by immunological methods which include Western blotting, dot blotting and double immunodiffusion techniques. Primary structure analysis of LC proteins (or key fragments thereof) will be coordinated by the Core. This will include compilation of the gene-deduced sequences from Project 1, as well as actual LC protein sequences on clinically-derived proteins used in Projects 2 and 3. In addition, all sequence information will e appropriate organized and available to Projects 1-4. The Core will utilize a variety of modalities include routine histological staining (H&E, PAS), special staining ) (Congo red and sulfated Alcian blue), immunohistochemistry, immunofluorescence, electron microscopy and immunoelectron microscopy techniques to evaluate and elucidate initial, midterm and late phases of amyloid deposition in animal and human tissue specimens for all projects, as well as cultured cell systems from Projects 1, 3 and 4.